Hello everyone, thanks for reading. So, this is pretty basic, but unfortunately I'm not sure of the answer - A fly is flying in a train, in the air, but isn't moving (one of these static-annoying flies). Then the train starts moving. The fly would then be seen to people sitting on the seats as though moving towards the back of the train, right? Then I thought - ok, the same thing has to happen with air molecules. But then - how come we don't feel "wind" when the train starts moving? Worse then that - how come we don't feel wind with the earth rotating around itself as rapidly as it does? Made me think I need to restudy Mechanics :-) Thanks a lot. Tomer.